I'll speak up about one concern I have. If MetaDataCache and ManagerImpl are stored in static references, I imagine it will be difficult to perform simultaneous/multi-threaded integration testing for webbeans apps. For example, with Seam, you can't have two SeamTests running at the same time in the same JVM, because Lifecycle.java has a static reference to the application map, and the two tests would interfere with each other. I'd be sad if the same thing occurs for the webbeans ri.
Now, maybe you could could use some ThreadLocal magic or something to avoid having to pass the ManagerImpl/metadatacache around everywhere in method calls. But my preference would be that the webbeans RI doesn't use static singletons at all.
What do you guys think?
-Matt